Depends on the person providing the thing. If you're ready to build some revenue from your thing, then yeah, upselling free customers when they need support seems like the natural thing to do.
However, there's another breed of hackers that enjoys making things more than they enjoy making money from things they make (which involves a different set of skills and interests). In which case, it's also valid to just say, "Sorry it's hard, but I can't commit to formal support."
Yeah, I think you did a better job of describing my dichotomy than I did. The galaxy brain corollary, though, is that if I get _too_ many folks who are asking for free-tier support, it means I can't support everyone at the level I'd like to; sort of a microscopic version of the OSS labor crisis.
However, there's another breed of hackers that enjoys making things more than they enjoy making money from things they make (which involves a different set of skills and interests). In which case, it's also valid to just say, "Sorry it's hard, but I can't commit to formal support."